Cats and Core Vaccines

What’s the latest in vaccine recommendation for cats? The American Association of Feline Practitioners (AAFP) released updated vaccine guidelines in 2013. Core vaccines for cats include feline panleukopenia virus (FPV), feline herpesvirus-1 (FHV-1), and feline calicivirus (FCV). Interestingly, rabies vaccine is included under the non-core category; however, the report notes that in states where rabies vaccination is required by law, the vaccine is “essential.” Let’s look at the diseases caused by these viruses, which helps to understand why they are considered core vaccines.

Feline panleukopenia virus (FPV): Sometimes called feline distemper, FPV is actually a parvovirus, and is closely related to the canine parvovirus I wrote about last week. The virus is highly contagious among cats and is found virtually everywhere, essentially meaning that all cats will be exposed to this virus in their lives. Infected cats shed virus in all of their bodily secretions, and other cats are exposed and infected when the virus enters their mouths or noses. The virus is very hardy in the environment, so long after the infected cat has stopped shedding virus, it will still be living and infectious to other cats. Once inside the cat’s body, the virus attacks all rapidly-growing cells, including white blood cells in the bone marrow and the cells lining the gut. Sadly, the white blood cells are needed to fight the infection, and without them, the cat is even more susceptible to the virus. Loss of the gut cells leads to severe diarrhea and dehydration, and cats develop secondary bacterial infections. The mortality (death) rate is around 90%. Thankfully, most kittens have some degree of immunity to this virus because it is so prevalent in the environment. This means that infection tends to be limited to young kittens kept in groups, where they are exposed to enough virus to overwhelm their variable degrees of immunity. Kittens that make it through 5 days of illness (with supportive care) typically survive, without long term side effects and with lifelong immunity. Mother cats that are infected during early or mid-pregnancy will lose their litters. If they are infected in late pregnancy, the virus will attack a portion of the kitten’s brain called the cerebellum, which is important for balance. These kittens are born with a condition called cerebellar hypoplasia, and they have great difficulty walking normally.

Feline Herpesvirus-1 (FHV-1) and Feline Calicivirus (FCV): I’m discussing these viruses together because they are the chief factors in the feline upper respiratory disease complex, accounting for about 90% of cases. We’ve all likely seen kittens or cats with weepy or crusty eyes, watery or thick nasal discharge, sneezing, mouth ulcers, and fever. Kittens take the brunt of this disease because they don’t have immunity as older cats do. I’ve treated some very sick little kittens with eyes and noses so crusted with discharge they can barely breathe and can’t see. Amazingly, with some TLC including warm compresses, oral antibiotics (for the secondary bacterial infections), eye ointment, and syringe feeding until they regain an appetite, most of these little ones will pull through. The illness usually lasts 7-10 days, but it’s important to realize that FHV-1 will lie dormant in the cat’s body for his or her lifetime and may become reactivated during periods of stress.

Core Vaccine Schedule

The AAFP report has a great set of overall objectives for vaccination. I like them so much I am going to list them here before I give you the schedule:

To vaccinate each cat only against infectious agents to which it has a realistic risk of exposure

To vaccinate against infectious agents that cause significant disease

To vaccinate a cat only when the potential benefits outweigh the potential risks

To vaccinate each cat no more frequently than necessary

To vaccinate the greatest number of cats possible in the population at risk

To vaccinate appropriately to protect human/public health

FPV/FHV-1/FCV Vaccination Schedule for Pet Cats

Kittens: begin at 6 weeks of age, repeat dose every 3-4 weeks until 16-20 weeks of age. Repeat booster in one year, then every three years.

Adult cats: give two doses, 3-4 weeks apart. Repeat booster in one year, then every three years.

Next week, we’ll look at non-core vaccines for cats and discuss titer testing in dogs and cats.